[GR-7441] Use VectorAccess in CastComplex/String/ExpressionNode.

.../com/oracle/truffle/r/nodes/builtin/base/AsCharacter.java

...rc/com/oracle/truffle/r/nodes/builtin/base/AsComplex.java

...com/oracle/truffle/r/nodes/builtin/MatchInternalNode.java

...cle/truffle/r/nodes/builtin/casts/PipelineToCastNode.java

...src/com/oracle/truffle/r/nodes/unary/CastComplexNode.java

.../com/oracle/truffle/r/nodes/unary/CastExpressionNode.java

.../com/oracle/truffle/r/nodes/unary/CastStringBaseNode.java

.../src/com/oracle/truffle/r/nodes/unary/CastStringNode.java

...le/truffle/r/runtime/data/nodes/FastPathVectorAccess.java

...le/truffle/r/runtime/data/nodes/SlowPathVectorAccess.java

...est/src/com/oracle/truffle/r/test/ExpectedTestOutput.test

...acle/truffle/r/test/builtins/TestBuiltin_ascharacter.java

...oracle/truffle/r/test/builtins/TestBuiltin_ascomplex.java

.../oracle/truffle/r/test/library/fastr/TestJavaInterop.java